The most common methods employed to control pathogens of plants of agronomic or horticultural interest include the use of large amounts of chemical products (fungicides, pesticides, etc.), some of which are classified as carcinogens and/or are toxic to animals and plants. Additionally, some pathogens can become resistant to said chemical products, making impossible their future use.
Biological control of phytopathogenic organisms constitutes a more attractive alternative than that involving chemical products. This alternative comprises the use of biological control agents which exist in nature and are in fact the natural enemies of the phytopathogenic organisms to be controlled. Biological control agents (live organisms and compounds produced by said organisms) are safer, more biodegradable and less deleterious to the environment than the chemical compounds usually employed to protect or treat plant diseases. However, the use of said biological control agents has been hindered by different causes, including the inadequate identification of biological control agents, which brings about reproducibility problems. One of the most important agents for the biological control of plant pathogens are the fungi belonging to the genus Trichoderma, some of which are capable of controlling a wide range of phytopathogenic organisms of great importance in agriculture. However, despite the relative success achieved, it has not yet been possible to reach the desired levels of control of plant diseases.